This invention relates to accumulator-reservoir type devices in which hydraulic or pneumatic pressures, or a combination of the two, are transmitted through a flexible diaphragm. The diaphragm has a bead at its periphery accommodated in a gland formed usually at mating ends of housing or shell sections. When the shell sections are bolted together, the diaphragm bead is fully contained in the gland. An annular opening in the gland allows the diaphragm wall adjacent to the bead to pass therethrough.
While the described structure is capable of anchoring the diaphragm bead and of effecting a seal at the provided joint it is so operable within a relatively low pressure range. Higher pressures exert an excessive pull on the diaphragm, causing bead portions to relax from or to move away from faces of the gland, breaking sealing contact therewith. In the past, high pressure requirements have been met by incorporating relatively massive flanges in the reservoir housing and heavily clamping a peripheral diaphragm portion between the flanges. Such a recourse is inconsistent with design objectives in aircraft and like accessories which favor small, lightweight constructions.